Process for preparing a sealed laminated vessel

Abstract

A sealed laminated vessel is formed from a barrel composed of a laminate including a paper substrate and a metal foil with inner and outer heat-sealable resin layers on both surfaces lapped together to form a straight side seam and a lid member on at least one open end thereof formed from a laminate of a metal foil and heat-sealable resin layer which is heat sealed to a circumferential end edge portion of the barrel. The vessel is formed by a process which includes forming a flat circumferential end portion of the barrel by bending at least one open end of the barrel outwardly and thereafter inwardly bending a part of the bent portion in the reverse direction so that it is lapped on the lower side of the remaining part of the bent portion to form a flat circumferential end portion on at least one open end of the barrel.The lid member is thereafter heat-sealed to the circumferential portion of the barrel through the heat-sealable resin layer of the lid member. Finally, the heat-sealed portion of the lid member and the circumferential end portion of the barrel are mechanically lap-seamed using a molding roller having a section conforming to the final shape of the sealed portion. As a result a horizontal flange wall in the peripheral portion of the lid member is downwardly bent together with the circumferential end portion of the barrel. Accordingly, heat sealing is uniformly effected and the sealing property is further improved by the mechanical lap seaming to form a tightly sealed laminated vessel.